Polyfluorinated sulfonic acids and derivatives



*Unimd ews P ent 2,871,161. I ,T'OLYFLUORINATEMD sUnroNIc-Acms DERIVATIVES George Van Dyke Tiers andRobert J. Koshar, St. Paul, f

. assignors to Minnesota Mining and Manufactut-ing Company, St. Paul, Minn., a-e'orporation of ndia W211 I No Drawing. Application..lune 18,1 956 Serial No. 591,811 r I 2 Claims; (CL-260 54 3) v .The present invention relate's toa newfand useful" class of reactive fluorocarboncompounds' and more particupounds from which the acids and-othersulfonylcom- 3 pounds can be made. The pei'fiuoromethylene (*QF groups linked together impart a highly stable and inert structure to the molecule. In addition these per'fluoro .groups provide a highly fiuorinated tail which is both oleophobic and hydrophobic to a ina'rked degree and' wh-ich imparts marked -surface activity to the molecule; Both water solubility and oil solubilityi'ncrease as the number of perfiuoromethylene groups decreases.

The terminal chlorine atom on "the end of-the tail provides higher boiling (and thus less volatile) co'mpounds more soluble in hydrocarbon solvents than their completely fiuorinated "'ar'ia'logs; some of which are dis closed and claimed in U. S. Patent 2,732,398 to Brice and'Trott. The presence of the terminal chlorine atom on the otherwise perfluorinated tail makes the present compounds useful in applications; such as surface active agents in aqueous or organic solutionsg'whe're the higher volatility and/or lower solubility of v the corresponding completely fluorinated compounds render them unsuitable.

The fluorosulfonyl-group (r -SO F) forms a reactive inorganic head" for the molecule, the sulfur atom being-united directly with the "terminal perfl'uorome'thylene group at the head end of the omega chlo'ro-perfiuoroalkyl tail, and further linked'to two oxygen atoms. The fluorine atom of the fiuoro'sul fonyl group'provides a reactive site for the attachment of other groups to the sul'-' fur atom in the formation of acids'and other derivatives. The omega-chloro-perfiuoi'oalkanesulfonyl fluorides are readily prepared by reacting tetrafiuoroethylene (CF =CF with sulfu'ryl clrlor'ofluoride '(SO' FCI) in the presence of an initiator for free' radieal polymerization at a temperature of C. to- 250 C., the reaction proceeding generally as illustrated by the reaction equation:

2 Making Organic SulfonylFluorides," Serial No. 595,013, filed on even date herewith.

Preparation of the novel compounds .of this invention in accordance with the process described in the aforementioned companion application is illustrated in the specific examples which follow.

ice

Example 1 In a '180' ml. autoclave was placed 40 g. SO FCI, 5.2 g. C F, (mol ratio 7:1) and 0.7 g. di-tertiar.y-butyl peroxide "(DTBP). The autoclave was sealed, and heated to 145" C. for 15 hours. The autoclave was then vented and a waxy dark brown solid recovered. The solid, after heating to 30 C. in vacuo to remove any DTBP decomposition products, showed an infrared band for. -SO F absorption at 6.8a. The average value of .,n in the formula Cl(CgF ),,S0 F was determined to be between 4 and 5 (approximately 4.5) by quantitative analysis.

Example 2 In a ml. stainless steel autoclave was placed 59 g. S0 E01, 21.4 g. C F (mol ratio 2.38:1) and 8.7 g. of ditertiary-butyl peroxide. The autoclave was sealed and heated at 140-145 C. for 16 hours with constant shaking. The autoclave wasvented at room temperatureand there was recovered 19.5 g. of solid product. Upon heating in a'sublimator at from 85-200" C., the solid reduced to a liquid fraction, two waxy sublimates and a powdery residue, all of which showed an infrared absorption band at 6.83-6.87u, which is characteristic of -S0 F absorption in perhaloalkyl sulfonyl fluorides. No elemental analysis of the liquid fraction was made because of the presence of infrared absorption characteristic of hydrogen-containing impurities. The elemental analyses. of the waxy sublimates and powdery residue, represent. ing a yield, based on starting C 1 of about 63%, w as follows; I

As in apparent from the examples, the predominance of fractions having large. or small average values of n in the general formula Cl(C F SO F may be controlled by varying the molar ratio of the reactants to one another. Molar ratios of SO FCl to CF CF of from 5:1 to 50:1, for example, favor the production of compounds'having n values which may range from 2 to about 50. Molar ratios of SO FCI to CF =CF of from 1:10 to 4:1, for example, favor the production of compounds having average n values which may run from about 50 to 150. Larger or smaller molar ratios than those mentioned do not adversely affect the reaction, however, and the indicated molar ratios are given primarily as a practical rule of thumb.

The omega-chloro-perfluoroalkanesulfonyl fluorides are useful intermediates in the preparation of a wide variety of fluorinated organic compounds and provide novel starting compounds from which the corresponding Example 3 A sealed ampoule of 10 ml. capacity, containing 2 ml. H 0, 67 mg. CaO (20% excess based on the weight of Cl(C F4) SO F) and 566 mg. 'Cl(C 'F4)4, SO F, is heated to l00 Cpwith agitation for four hours, cooled, and opened, the reaction proceeding generallyasillus trated by the reaction equation:

To "convert unreacted calcium hydroxide, to insoluble CaCO carbon dioxide is bubbled into the reaction mixture.

The mixture is filtered to remove the precipitate of approximately 130 C., pure crystalline.

water, a saturated aqueous solution thereof at room tem perature (25 C.) containing about 20% salt by weight.

The zinc salt [Cl(C F SO Zn, rnay be prepared from the calcium salt by the addition of the calculated amount of zinc sulfate (ZnSO in aqueous solution to a hot (60-70 C.) aqueous solution of the calcium salt, the calcium precipitating out of solution as CaSO This zinc salt is itself quite soluble in water, a saturated. solution thereof at room temperature containing about 10% by weight of the zinc salt.

' The potassium, lithium, ammonium and sodiumsalts;

an) 4.5 s

is prepared by distillation from a mixture of the calcium 60 or other salt and 100% sulfuric acid solution.

The sulfonyl chlorides Cl(C F ),,SO Cl can be prepared by reacting the acid with PCI orthe'salt and ammonium salts, acid chlorides as other derivatives" may b rs garage;

" with reg-225a,- eiiih ix in approximately equal son'- The sulfonamides Cl(C F4),,SO- -NH may be prepared by the formula l t -,ct cn=i)..sozA

an integer "steels: to about 150 and wherein A is an inorganic substituent representing a sulfur bonded (OM), (with the understanding that in the case of salts or polyvalent metals the metal atom may be joined to more than one sulfonyl group) ora fluorine (F) or chlorine (Cl) atom in the cases of acid fluorides or chlorides, oranamido group (NH in the case of sulfonamides.

The saltsland the acidsare extremely stable. The acids are stronger, more sol uble, much higher boiling, and less volatile than the corresponding perfiuoro carboitylic acids}, Both the acids and their salts are more stable than their s d u arbox lic counter arts. and ar calcium fluoride and calcium carbonate and upon evapo Eon-mg pert-119m p a ration of the filtrate on a steam bath and oven drying at stronger} and more stable than their hydrocarbon sulfonio counterparts.

The omega-chloroperfluoroalkanesulfonic acids and derivativeshave utility ;as surface active agents and as;

is obtained. This calcium salt is remarkably soluble in; starting materials" for making smfacg activeicompounrds' Although the omega-chloro-substituent on the otherwise:

completelyfluorinated tail renders these compounds markedly less oil .resistant than their corresponding analogs having completely fluorinated tails, the omega-;

v 1 chloro-compoundsnevertheless are only slightly soluble 1 nated compounds render them unsuitable.

.7 Specifically, the omega-chloro-perfiuoroalkanesulfonic1 gents, corrosion inhibitors, fluxes and as surface treating inhydrocarbons, oils and carbon tetrachloride and are, useful to reduce the surface tension of aqueous and non-; aqueous solutions where. the higher volatility and/or. lower solubility ofthecorresponding completely fluori-.

acids and derivatives of this invention have utility (depending on the particular system) as wetting agents, foam-. rug-agents, emulsifying agents, dispersing agents, deter? and coating agents.

Having thus described,theinvention, what is claimed;

as new is as follows:

We, claim:

a 1. The omega-chloroperfluoro alkanesulfonic acids; I

represented by the formula 1 CKCzFOn s wheat-s n is: all integer new about 2 to about 150, and: the corresponding metal and ammonium salts, acid flue- References cited'in the fileof this patent UNITED STATES PATENTS 2,276,097 Salzberg Mar. 10,4942 1,732,398 Brice etal. Jan'- ED STATES PATENT OFFICE UNIT CERTIFICATE OF CORRECTION Patent No 2,877,267 March 10, 1959 George Van Dyke Tiers et a1.

8 in the printed specification d Letters tif-ied that error appear atent requiring corre tion and that the em It is hereby cer ted below.

of the above numbered p Patent should readas correc 16, for or polyvalent rea Column A, line Signed and sealed this 22nd day of March 1960.

(SEAL) Attest:

ROBERT C. WATSON Commissioner of Patents KARL Ii. AX TNE Attesting Officer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,877,267 March 10, 1959 George Van Dyke Tiers et al0 It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should readas corrected below.

Column 4, line 16, for "or polyvalent" read of polyvalent Signed and sealed this 22nd day of March 1960.

(SEAL) Attest:

ROBERT C. WATSON Commissioner of Patents KARL H. AXLINE Attesting Ofiicer UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,877,267 March 10, 1959 George Van Dyke Tiers et al., 7

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction and that the said Letters Patent should readas corrected below.

Column 4, line 16, for or polyvalent" read of polyvalent Signed and sealed this 22nd day of March 1960.

(SEAL) Attest:

KARL H. AXLINE to ROBERT C. WATSON Attesting Oflicer v Commissioner of Patents 

1. THE OMEGA-CHLORO-PERFLUORO ALKANESULFONIC ACIDS REPRESENTED BY THE FORMULA 